Most power electronic applications require knowledge of the current in the system, either in the load or in the switches. This is usually used to protect the system, the power conversion devices or to enhance system performance. Current monitoring is done in many ways such as by current transformers (xe2x80x9cCTsxe2x80x9d), shunt resistors, current sensing devices and DC current probes based on Hall effect devices which are coupled with gapped core and coil assemblies. Current transformers cannot be used in applications that require sensing of low frequency currents. Shunt resistors are limited in their application range to a maximum of a few tens of amperes. DC current probes based on the Hall effect are expensive and add cost to the system assembly.
In accordance with the invention, the driver printed circuit board (xe2x80x9cPCBxe2x80x9d) of a power module carries a current sensor such as commercially available Hall effect device (without magnetics) disposed at an edge of the board and positioned in the magnetic field that is created by the conductors carrying the current to and from the module. Magnetic bars or bodies may also be fastened to the board to focus or increase flux in the current sensor.
Some of the features of the present invention are:
1. Including a Hall effect or other current sensing assembly such as magnetostrictive devices in the module and placing it in a position to detect the field.
2. Ensuring a way to place the current sensor device in an accurate orientation with respect to the current carrying conductor.
3. Using the output of the device to trip a comparator to protect the switches or system.
4. Making the output of the device available to a controller for improving system performance.
5. In cases where the current is not strong enough to create the requisite magnetic field, adding appropriate bars of ferrite, iron or similar ferro magnetic material which allows an increase in the flux density through the sensor for a given current.
6. Bending the current carrying conductor whose current is to be measured in a particular direction to increase or decrease the amount of flux in the sensing device.